The present invention relates to frequency sweeps, and more particularly to such sweeps operating in the radio frequency range.
Many communication devices utilize frequency sweeps, e.g., demodulators, swept receivers and spectrum analyzers. A frequency sweep is a device the output of which is a monotonic frequency function of time.
Frequency sweeps are often produced by time dispersing a pulse as a function of frequency. The pulse is selected to have frequency components over the desired output range of the sweep.
One such dispersion device is a "reflective array compressor" (RAC). The RAC may be manufactured by etching plural slits in a large quartz crystal. The size and placement of the slits determine the dispersion characteristics of the RAC. For example, a RAC may be designed to provide a linear or other specific sweep.
While RACs perform quickly and reliably, they are difficult to manufacture precisely. A RAC designed to produce a linear frequency sweep will generally have some characteristic non-linearities. The cost of manufacturing each RAC typically prohibits large scale rejection of deviating devices.